1. Field of the Invention
This invention generally relates to a bicycle pedal. More specifically, the present invention relates to a clipless or step in bicycle pedal.
2. Background Information
In recent years, bicycle pedals have been designed for specific purposes such as for pleasure, off road biking, road racing, etc. One particular type of bicycle pedal, which is gaining more popularity, is the step-in or clipless pedal, which releasably engages a cleat secured to the sole of a cyclist's shoe. The clipless pedal has a pedal spindle that can be mounted on the crank of a bicycle, a pedal body that is rotatably supported on this pedal spindle, and a cleat engagement mechanism. In an off road bicycle pedal the cleat engagement mechanism front and rear cleat clamping members that are fixed on both sides of the pedal body for engaging front and rear portions of a cleat. Road racing pedals typically only has a cleat engagement mechanism on one side of the pedal body. In either case, in this type of bicycle pedal, the rider steps onto the pedal and the cleat engagement mechanism automatically grips on to the cleat secured to the bottom of the cyclist's shoe.
More specifically, when attaching the cyclist's shoe to the step-in pedal via the cleat, the cyclist moves the shoe obliquely downwardly and forwardly relative to the pedal body such that the front end of the cleat engages a front hook or clamping member of the pedal body. Once the front end of the cleat is engaged with the front hook of the pedal body, the cyclist places the rear end of the cleat in contact with a guide portion of the rear hook or clamping member of the pedal body. In this position, the cyclist presses the shoe downwardly against the pedal to cause the rear hook or clamping member to initially pivot rearwardly against the force of a spring to move the rear hook or clamping member to a cleat releasing position. The rear end of the cleat then enters a position opposite a back face of the rear hook or clamping member. Then, the rear hook or clamping member returns under the force of a biasing member or spring so that the rear hook or clamping member engages the rear end of the cleat. This engagement fixes the cyclist's shoe to the pedal via the cleat.
When releasing the shoe from the pedal, the cyclist will typically turn the shoe about an axis perpendicular or approximately perpendicular to the tread of the pedal, using the front end of the cleat as a pivoting point. As a result of this pivoting action, the rear hook or clamping member is pivoted rearwardly against the force of the spring to a cleat releasing position to release the shoe.
When step-in pedals are used for road type bikes, the pedal is typically only provided with a single clamping assembly such that the cyclist's shoe can only be coupled to one of the two sides of the pedal. Off road or mountain type bikes, on the other hand, usually have a pair of clamping assemblies such that the cyclist's shoe can be clamped to either side of the pedal. In either case, it is desirable to design the pedal to be as compact and lightweight as possible.
One problem with most clipless pedals is that they are quite small such that only small portions of the pedal body engage the rider's shoe. Specifically, the pedal body has a tread surface located on both sides of the cleat engagement mechanism. This tread surface has only a small surface area because the pedal body is typically made as small as possible so that it will be lightweight. With this type of clipless pedal, the shoe and the pedal are in a state of constant engagement when the cleat clamping is engaged in the cleat clamping members, so the pedaling force can be transmitted efficiently to the pedals. As a result, clipless pedals are widely employed on racing bicycles used in road racing and mountain bike racing.
With this type of clipless pedal, if the shoe and the pedal are loose to the right and left around the cleat clamping members, then the rider's foot will wobble to the right and left and the rider's pedaling force will not be transmitted efficiently to the pedal. Therefore, any looseness to the right and left between the shoe and pedal should be suppressed to a minimum by having the rubber portion of the shoe sole come into contact on the right and left of the cleat with a tread surface provided to the pedal body.
The conventional structure described above merely consists of bringing the rubber portion of the shoe sole into contact with a tread surface having a tiny surface area in order to suppress looseness to the right and left of the shoe. Therefore, the contact length is minimal, and it is difficult to suppress properly the looseness to the right and left. Moreover, since the portion of the shoe sole that is in contact with the tread surface is the same portion that comes into contact with the ground when the rider is walking, it tends to wear down, and when this portion of the sole wears down, the tread surface and the shoe sole no longer come into contact uniformly, making it difficult to suppress the looseness between the shoe and pedal.
Downhill races, dual slalom races, cross-country races, and other such off-road races for mountain bikes and BMX (bicycle motocross) have been widely staged in recent years. In this type of off-road race, unlike in road racing, the riders traverse an unpaved track. Furthermore, with this type of off-road racing the foot must be repeatedly taken off the pedal during cornering and replaced on the pedal after the comer has been exited. Unfortunately, since the racing is performed on unpaved roads, mud clings to the pedals and tends to clog the cleat clamping members. Once the cleat clamping members become clogged with mud, the cleat cannot be engaged in the cleat clamping members, and the shoe cannot be attached to the pedal. Moreover, the mud often clogs the biasing mechanism such that the clamping members may not operate properly.
In view of the above, there exists a need for a bicycle pedal which overcomes the above mentioned problems in the prior art. In view of the above, it is apparent that there exists a need for a clipless bicycle pedal which works well in dirty and muddy environments. This invention addresses these needs in the art, along with other needs, which will become apparent to those skilled in the art once given this disclosure.